Pulsed dye laser-induced europium (III) and terbium (III) ion luminescence probe experiments for the study of the structure and function of calcium-binding proteins will be further developed and exploited. With the capability of measuring metal ion binding in the namomolar concentration range a general, site-specific method of determining the thermodynamic parameters of metal ion-protein interactions will be established. Calmodulin, the ubiquitous intracellular calcium-modulated regulatory protein, will be extensively studied with regard to its metal ion binding properties and its interaction with target enzymes and drug molecules. These studies will be aided by a newly developed, continuous, spectrophotometric assay for calmodulin based on the activation of NAD kinase. The calmodulin-NAD kinase interaction will be probed in depth. Laser spectroscopic experiments will be carried out on other calcium-modulated proteins including parvalbumin and calcineurin as well as on phospholipase A2, glutamine synthetase, and proteins of the blood coagulation cascade through collaborative arrangements. Luminescence or fluorescence-monitored stopped-flow kinetic studies of metal ion disociation from calmodulin and other calcium-modulated proteins will be carried out. The role of metal ion binding in the dynamics of protein folding or unfolding will be examined.